Fluid end with non-circular bores and closures for the same

ABSTRACT

A method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly includes inserting a non-circular closure element into a segment of a fluid end casing in a first direction while the non-circular closure element is disposed in a first orientation. The non-circular closure element is rotated to a second orientation that is angularly offset from the first orientation with respect to at least one axis of rotation. The non-circular closure element is further moved within the segment of the fluid end casing in a second direction that is opposite the first direction to cause the non-circular closure element to seat within the segment.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 17/725,929, filed on Apr. 21, 2022, and entitled “Fluid End with Non-Circular Bores and Closures For The Same,” the disclosure of which is incorporated by reference in entirety.

FIELD OF INVENTION

The present invention relates to the field of high pressure reciprocating pumps and, in particular, to fluid ends of high pressure reciprocating pumps and closure and/or sealing assemblies for the same.

BACKGROUND

High pressure reciprocating pumps are often used to deliver high pressure fluids during earth drilling operations. One or more sealing arrangements are typically provided in the fluid end to seal conduits formed in the fluid end and prevent, or at least discourage, leakage. More specifically, the fluid end may define one or more internal pumping chambers and conduits may define pathways between the one or more internal pumping chambers and external surfaces of the fluid end. At least some segments of these conduits may be sealed with a closure assembly that may include a closure element (e.g., a cover, plug, and/or sleeve), a seal element, and a retaining element. Alternatively, a closure assembly may include some subset of these elements. In any case, seals in a fluid end segment may prevent, or at least discourage, leakage through the conduits of a fluid end.

SUMMARY

The present application relates to techniques for closing a segment of a fluid end of a high pressure reciprocating pump. The techniques may be embodied as a closure element and/or a closure assembly, either of which may be provided independent of any other elements or as part of a fluid end, a kit, and/or a reciprocating pump. Additionally, the techniques may be embodied as a fluid end and as a method for closing a segment of a fluid end of a high pressure reciprocating pump.

More specifically, in accordance with at least one embodiment, the present application is directed to a closure element for a fluid end of a reciprocating pump. The closure element is installable within a segment of a casing of the fluid end to substantially close the segment and includes a main body that extends from an interior surface to an exterior surface. At least a portion of the main body has a non-circular cross-sectional shape.

Among other advantages, the non-circular shape creates sealing and retaining options that may be advantageous as compared to traditional sealing and retaining techniques. For example, the closure element may be self-retaining and/or may be retained within a bore without threading, which is often a high-stress point that is prone to failure. More specifically, closure elements are often secured in a segment with a retaining element that is secured to a fluid end via a threaded connection formed between threads machined into the fluid end and threads of the retaining element. These threads are typically subject to high levels of cyclical stress and, thus, if the retaining element is not installed or preloaded correctly, the threads may experience fatigue failure.

Still further, the non-circular cross-sectional shape allows a sealing location to move inwards, adjacent a pumping chamber, or outwards, adjacent an exterior of the fluid end, each of which may provide additional life span advantages for the closure element and/or the fluid end within which the closure element is installed. For example, a closure element with a non-circular cross-sectional shape may be retained adjacent the pumping chamber of a fluid end and may protect the interior edges of a fluid end segment, which are often a point of failure, from wear. Additionally or alternatively, when the closure element is retained adjacent the pumping chamber or external surface, the closure element can define a corner for a corner seal, which may avoid traditional pitfalls associated with radial seals (i.e., outer diameter seals) used on closure elements for fluid ends. For example, when a closure element has a non-circular cross-sectional shape, a bore or corner seal may be used to seal around the closure element. Still further, in some instances, the sealing area can be located on a removable piece. Then, if the sealing surface becomes damaged (which typically happens over time during normal pumping operation), the sealing area can be repaired via a part replacement instead of via an invasive repair (e.g., a weld repair).

In at least some embodiments, the non-circular cross-sectional shape is an extended ovular shape. This shape may ensure that the closure element is removable from, but also securable within, a bore segment of a fluid end. Additionally or alternatively, the main body may include a seating section proximate the interior surface and a closure section proximate the exterior surface, one or both of which may have the non-circular cross-sectional shape. For example, the seating section may extend radially beyond the closure section, the seating section may have a first non-circular cross-sectional shape, and the closure section may have a second non-circular cross-sectional shape that is smaller than the first non-circular cross-sectional shape. Alternatively, the seating section may extend radially beyond the closure section and only one of the seating section and the closure section may include the non-circular cross-sectional shape. In either case, the two sections may allow the closure element to be secured within the fluid end, e.g., against the fluid end and/or a retaining element, and/or to form a corner seal when secured within a fluid end bore segment.

In at least some instances where the seating section extends radially beyond the closure section, the seating section may define a non-circular shoulder between the seating section and the closure section. In some of these embodiments, the closure section defines a seal channel adjacent or proximate to the non-circular shoulder. Either way, this allows some flexibility for the sealing area and may, advantageously, move the sealing area away from locations that are hard to repair. Still further, in some embodiments, the closure element includes one or more installation elements disposed on and extending away from the exterior surface so that that the one or more installation elements are accessible from an exterior of the segment of the casing of the fluid end when the closure element is installed within the segment. Such elements may enable a user to easily install or remove the closure element from a fluid end bore segment.

In accordance with additional embodiments, the present application is directed to a closure assembly. The closure assembly may be formed with the foregoing closure element embodiments, as well as variations thereof. Thus, the closure assembly may realize any of the foregoing advantages. Additionally, the closure assembly may include a retaining assembly that is coupleable to the exterior surface of the closure element. Generally, the retaining assembly may prevent, or at least discourage, the closure element from being blown out (i.e., removed) of a bore segment, e.g., by pressure in a pumping chamber. In some embodiments, the retaining assembly may also prevent, or at least discourage, the closure element from being sucked into a pumping chamber of the fluid end (e.g., during an intake stroke of a reciprocating component operating in or adjacent the fluid end).

In at least some embodiments, the retaining assembly also includes couplers that removably couple a retaining element to the closure element. Additionally or alternatively, the retaining assembly may be configured to be disposed entirely within the segment of the casing of the fluid end when the closure element is installed within the segment of the casing of the fluid end. In fact, in such embodiments, the retaining assembly may appear to be part of the closure element and, thus, such embodiments may sometimes be referred to as “two-part closure element” embodiments. Among other advantages, such embodiments may allow a closure element to seal adjacent a pumping chamber, potentially reducing the size of the pumping chamber, which is advantageous for pumping compressible fluids. Additionally or alternatively, a retaining assembly disposed within a fluid end bore may reduce the overall footprint of a fluid end (since the retaining assembly does not extend therefrom), potentially reducing snag/trip hazards around the fluid end (e.g., as compared to retaining assemblies that protrude from a fluid end).

Alternatively, in some instances, at least a portion of the retaining assembly is configured to be disposed at least partially exteriorly of the casing of the fluid end when the closure element is installed within the segment of the casing of the fluid end. For example, the retaining assembly may include a retainer, such as an annular retaining ring with a non-circular cross section, disposed exteriorly of the casing of the fluid end. The retainer can define a seat on which a shoulder of the portion of the main body of the closure element with the non-circular cross-sectional shape may sit. Then, the sealing area for the closure element may be formed against this annular ring, which can be easily repaired or replaced (e.g., without invasive repairs). Moreover, in at least some embodiments, the retainer may be secured to a fluid end with a plurality of couplers, but need not be removed to replace the closure element. Instead, the non-circular cross-sectional shape of the closure element may allow the closure element to be replaced or serviced quickly, without removing plurality of couplers (e.g., by rotating the closure element into an installation/removal orientation while the retainer remains in place).

In accordance with additional embodiments, the present application is directed to a fluid end of a reciprocating pump including a casing with intersecting conduits that collectively define a plurality of segments extending from an external surface of the casing to a pumping chamber defined within the casing. At least a portion of at least one segment of the plurality of segments has a non-circular cross-sectional shape configured to receive and secure a closure element with a non-circular cross-sectional shape. At least because of the non-circular cross-sectional shape, this fluid end may realize many of the advantages discussed above in connection with the closure elements and/or the closure assemblies presented herein.

In some embodiments, the plurality of segments include an intake segment that provides a fluid inlet for the pumping chamber, a discharge segment that that provides a fluid outlet for the pumping chamber, a reciprocation segment, and an access segment. The reciprocation segment is configured to operably couple a reciprocating component to the pumping chamber so that the reciprocating component can draw fluid into the pumping chamber via the intake segment and discharge fluid from the pumping chamber via the discharge segment. The access segment provides access to at least the pumping chamber. In some instances, the access segment has the non-circular cross-sectional shape. Additionally or alternatively, the discharge segment may have the non-circular cross-sectional shape.

Regardless of the segments included in a fluid end, the portion of the at least one segment of the plurality of segments that has the non-circular cross-sectional shape may comprise a segment portion adjacent to the pumping chamber. Alternatively, the portion of the at least one segment of the plurality of segments that has the non-circular cross-sectional shape may comprise a segment portion adjacent to the external surface of the casing.

In accordance with additional embodiments, the present application is directed to a method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly. The method includes inserting a non-circular closure element into a segment of a fluid casing in a first direction while the non-circular closure element is disposed in a first orientation. Then, the non-circular closure element is rotated to a second orientation that is angularly offset from the first orientation with respect to at least one axis of rotation. After and/or during the rotation, the non-circular closure element is moved within the segment of a fluid casing in a second direction. The second direction is opposite the first direction and, thus, causes the non-circular closure element to seat within the segment. In some of these embodiments, the rotating occurs in a pumping chamber of the fluid end and involves a first rotation of approximately ninety degrees about a first axis of rotation and a second rotation of approximately ninety degrees about a second axis of rotation.

Notably, among other advantages, the closure element can be seated into a bore segment without a retaining element and/or without threading. At least because this method utilizes a non-circular closure element, this method may also realize any advantages described above. This method may also be executed with any variations of closure elements or closure assemblies described herein.

The foregoing advantages and features will become evident in view of the drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

To complete the description and in order to provide for a better understanding of the present application, a set of drawings is provided. The drawings form an integral part of the description and illustrate embodiments of the present application, which should not be interpreted as restricting the scope of the invention, but just as examples. The drawings comprise the following figures:

FIG. 1 is a perspective view of a prior art reciprocating pump including a fluid end.

FIG. 2 is a cross sectional view of another prior art fluid end.

FIG. 3 is a front view of a fluid end with a non-circular bore that has non-circular closure assemblies installed therein. The fluid end and closure assemblies are each formed according to example embodiments of the present application.

FIG. 4 is a side, sectional view of the fluid end of FIG. 3 taken along line “A-A” of FIG. 3 .

FIG. 5 is a perspective view of one of the closure assemblies installed in the fluid end of FIGS. 3 and 4 .

FIG. 6 is a front, sectional view of the fluid end of FIG. 3 taken along line “A-A” of FIG. 4 , with the closure assembly removed from the fluid end.

FIG. 7 is a detail view of a portion of the sectional view of FIG. 4 with the closure assembly removed from the fluid end.

FIG. 8A is a detail view of portion “B” of the sectional view of FIG. 4 .

FIG. 8B is a front perspective view of a retaining element that may be used with at least a closure element of the closure assembly of FIG. 3 , according to an example embodiment.

FIG. 8C is a schematic, sectional view of the retaining element of FIG. 8B while installed on the closure element of the closure assembly of FIG. 3 .

FIG. 8D is a front perspective view of another example embodiment of a closure element that may be used with at least a retaining element of the closure assembly of FIG. 3 .

FIG. 8E is a rear perspective view of the closure element of FIG. 8D.

FIG. 8F is a side, sectional view of the closure element of FIG. 8D, taken along line A-A of FIG. 8E.

FIG. 8G is a front perspective view of yet another example embodiment of a closure element that may be used with at least a retaining element of the closure assembly of FIG. 3 .

FIG. 8H is a side perspective view of the closure element of FIG. 8G assembled with a retaining element to form at least a portion of a closure assembly.

FIG. 8I is a schematic, front sectional view of a fluid end embodiment with the closure assembly removed from the fluid end.

FIG. 9 is a side, sectional view of a portion of another example embodiment of a fluid end with a non-circular bore formed in accordance with the present application.

FIG. 10 is a perspective view of a second embodiment of a closure assembly formed in accordance with the present application.

FIG. 11A is a front view of a portion of the fluid end of FIG. 3 with a third embodiment of the closure assembly presented herein installed therein.

FIG. 11B is a side, sectional view of the fluid end and closure assembly of FIG. 11A.

FIG. 12A is a front view of a portion of the fluid end of FIG. 3 with a variation of the third embodiment of the closure assembly presented herein installed therein.

FIG. 12B is a side, sectional view of the fluid end and closure assembly of FIG. 12A.

FIG. 13 is a side, sectional view of another example embodiment of a fluid end with a non-circular bore including a fourth embodiment of the closure assembly installed therein. The fluid end and closure assembly are each formed according to example embodiments of the present application.

FIG. 14 is a perspective view of the closure assembly shown in FIG. 13 .

FIG. 15 is a detail view of portion “B” of the sectional view of FIG. 13 .

FIG. 16A is a side perspective, sectional view of yet another example embodiment of a fluid end with a non-circular bore including a fifth embodiment of the closure assembly presented herein installed therein. The fluid end and closure assembly are each formed according to example embodiments of the present application.

FIG. 16B is a front view of the fluid end of FIG. 16A, with a closure element of the closure assembly for the fluid end being shown in an installation orientation.

FIG. 17A is a front perspective view of yet another example embodiment of a fluid end with a non-circular bore including a variant of the fifth embodiment of the closure assembly presented herein installed therein. The fluid end and closure assembly are each formed according to example embodiments of the present application.

FIG. 17B is a sectional view of the fluid end and closure assembly of FIG. 17A taken along line A-A of FIG. 17A.

FIGS. 18A-18E depict a method of closing an externally open segment of a fluid end of a reciprocating pump with a non-circular closure assembly, according to an example embodiment of the present application.

FIG. 19 depicts a final assembly formed when executing the method of FIGS. 18A-18E in accordance with an example embodiment of the present application.

Like reference numerals have been used to identify like elements throughout this disclosure.

DETAILED DESCRIPTION

The following description is not to be taken in a limiting sense but is given solely for the purpose of describing the broad principles of the invention. Embodiments of the invention will be described by way of example, with reference to the above-mentioned drawings showing elements and results according to the present invention.

Generally, the present application is directed to a fluid end of a reciprocating pump, closure assemblies for the fluid end, and/or portions thereof. The fluid end presented herein has at least one bore with a non-circular cross-sectional shape while the closure assemblies presented herein include least some components or sections with non-circular cross-sectional shapes. Typically, fluid ends for reciprocating pumps have bores with circular cross-sectional shapes (e.g., cylindrical bores) while closure elements therefor (e.g., valve covers, plugs, sleeves, etc.) have corresponding circular/cylindrical shapes to allow the closure elements to close and/or seal the bore.

These circular/cylindrical closure elements are typically secured in a bore segment with a threaded retaining element that engages threads machined into the fluid end. Such an arrangement creates at least two issues. First, a cylindrical closure element secured in a cylindrical bore can define sealing areas on the inner surface of the bore. This surface is often defined by the fluid end and, thus, can be very difficult to repair (e.g., repair may require an invasive weld repair). Second, with such an arrangement, the threads on the retaining element are subject to high levels of cyclical stress. Thus, if the retaining element is not preloaded correctly, the threads may experience fatigue failure.

The closure assemblies and/or the fluid end presented herein resolve these issues and, thus, can extend the lifespan of both the fluid end and the closure element. Initially, in at least some embodiments, a closure element with a non-circular cross-sectional shape can be secured within a fluid end bore without a threaded retaining element, thereby eliminating a potential point of failure. Instead, the closure element can be retained directly on a fluid end and/or on a retaining element that is fixed in place on a fluid end (e.g., the retaining element need not be removed for installation or removal of the closure element). This may also make the closure assembly easy to install, decreasing the amount of time required for installation and/or removal which, in turn, decreases downtime. Moreover, in at least some embodiments where a seal disposed around a closure element seals against a retaining element, the fluid end will not define a sealing area and, thus, will not experience wear associated with the sealing area. Additionally or alternatively, the non-circular cross-sectional shapes of the present application may allow the seals to be/provide bore or corner seals, which may be more robust than radial seals (e.g., seals between nested components of different radial dimensions).

Now referring to FIG. 1 for a description of a prior art reciprocating pump 100. The reciprocating pump 100 includes a power end 102 and a fluid end 104. The power end 102 includes a crankshaft that drives a plurality of reciprocating plungers within the fluid end 104 to pump fluid at high pressure. Generally, the power end 102 is capable of generating forces sufficient to cause the fluid end 104 to deliver high pressure fluids to earth drilling operations. For example, the power end 102 may be configured to support hydraulic fracturing (i.e., fracking) operations, where fracking liquid (e.g., a mixture of water and sand) is injected into rock formations at high pressures to allow natural oil and gas to be extracted from the rock formations. However, to be clear, this example is not intended to be limiting and the present application may be applicable to both fracking and drilling operations.

Often, the reciprocating pump 100 may be quite large and may, for example, be supported by a semi-tractor truck (“semi”) that can move the reciprocating pump 100 to and from a well. Specifically, in some instances, a semi may move the reciprocating pump 100 off a well when the reciprocating pump 100 requires maintenance. However, a reciprocating pump 100 is typically moved off a well only when a replacement pump (and an associated semi) is available to move into place at the well, which may be rare. Thus, often, the reciprocating pump is taken offline at a well and maintenance is performed while the reciprocating pump 100 remains on the well. If not for this maintenance, the reciprocating pump 100 could operate continuously to extract natural oil and gas (or conduct any other operation). Consequently, any improvements that extend the lifespan of components of the reciprocating pump 100, especially typical “wear” components, and extend the time between maintenance operations (i.e., between downtime) are highly desirable.

Still referring to FIG. 1 , but now in combination with FIG. 2 , in various embodiments, the fluid end 104 may be shaped differently and/or have different features, but may still generally perform the same functions, define similar structures, and house similar components. To illustrate potential shape variations, FIG. 2 shows a side, sectional view of a fluid end 104′ with different internal and external shaping as compared to fluid end 104. However, since fluid end 104 and fluid end 104′ have many operational similarities, FIGS. 1 and 2 are labeled with the same reference numerals and are both described with respect to these common reference labels.

The sectional view of FIG. 2 is taken along a central or plunger axis of one of the plungers 202 included in a reciprocating pump 100. Thus, although FIG. 2 depicts a single pumping chamber 208, it should be understood that a fluid end 104 can include multiple pumping chambers 208 arranged side-by-side. In fact, in at least some embodiments (e.g., the embodiment of FIG. 1 ), a casing 206 of the fluid end 104 forms a plurality of pumping chambers 208 and each chamber 208 includes a plunger 202 that reciprocates within the casing 206. However, side-by-side pumping chambers 208 need not be defined by a single casing 206. For example, in some embodiments, the fluid end 104 may be modular and different casing segments may house one or more pumping chambers 208. In any case, the one or more pumping chambers 208 are arranged side-by-side so that corresponding conduits are positioned adjacent each other and generate substantially parallel pumping action. Specifically, with each stroke of the plunger 202, low pressure fluid is drawn into the pumping chamber 208 and high pressure fluid is discharged. But, often, the fluid within the pumping chamber 208 contains abrasive material (i.e., “debris”) that can damage seals formed in the reciprocating pump 100.

As can be seen in FIG. 2 , the pumping paths and pumping chamber 208 of the fluid end 104 are formed by conduits that extend through the casing 206 to define openings at an external surface 210 of the casing 206. More specifically, a first conduit 212 extends longitudinally (e.g., vertically) through the casing 206 while a second conduit 222 extends laterally (e.g., horizontally) through the casing 206. Thus, conduit 212 intersects conduit 222 to at least partially (and collectively) define the pumping chamber 208. In the prior art fluid end 104 and prior art fluid end 104′, conduits 212 and 222 are substantially cylindrical, but the diameters of conduit 212 and conduit 222 may vary throughout the casing 206 so that conduits 212 and 222 can receive various structures, such as sealing assemblies or components thereof.

Regardless of the diameters of conduit 212 and conduit 222, each conduit may include two segments, each of which extend from the pumping chamber 208 to the external surface 210 of the casing 206. Specifically, conduit 212 includes a first segment 2124 and a second segment 2126 that opposes the first segment 2124. Likewise, conduit 222 includes a third segment 2224 and a fourth segment 2226 that opposes the third segment 2224. In the depicted embodiment, the segments of a conduit (e.g., segments 2124 and 2126 or segments 2224 and 2226) are substantially coaxial while the segments of different conduits are substantially orthogonal. However, in other embodiments, segments 2124, 2126, 2224, and 2226 may be arranged along any desired angle or angles, for example, to intersect pumping chamber 208 at one or more non-straight angles.

In the depicted embodiment, conduit 212 defines a fluid path through the fluid end 104. Segment 2126 is an intake segment that connects the pumping chamber to a piping system 106 delivering fluid to the fluid end 104. Meanwhile, segment 2124 is an outlet or discharge segment that allows compressed fluid to exit the fluid end 104. Thus, in operation, segments 2126 and 2124 may include valve components 51 and 52, respectively, (e.g., one-way valves) that allow segments 2126 and 2124 to selectively open. Typically, valve components 51 in the inlet segment 2126 may be secured therein by a piping system 106. Meanwhile valve components 52 in outlet segment 2124 may be secured therein by a closure assembly 53 that, in the prior art example depicted in FIG. 2 , includes a closure element 251 (also referred to as a discharge plug) that is secured in the segment 2124 by a retaining assembly 252. Notably, the prior art retaining assembly 252 is coupled to segment 2124 via threads 2128 defined by an interior wall of segment 2124.

On the other hand, segment 2226 defines, at least in part, a cylinder for plunger 202, and/or connects the casing 206 to a cylinder for plunger 202. For example, in the depicted embodiment, a casing segment 35 is secured to segment 2226 and houses a packing assembly 36 configured to seal against a plunger 202 disposed interiorly of the packing assembly 36. In any case, reciprocation of a plunger 202 in or adjacent to segment 2226, which may be referred to as a reciprocation segment, draws fluid into the pumping chamber 208 via inlet segment 2126 and pumps the fluid out of the pumping chamber 208 via outlet segment 2124. Notably, in the depicted prior art arrangement, the packing assembly 36 is retained within casing segment 35 with a retaining element 37 that is threadably coupled to casing segment 35.

Segment 2224 is an access segment that can be opened to access to parts disposed within casing 206 and/or surfaces defined within casing 206. During operation, access segment 2224 may be closed by a closure assembly 54 that, in the prior art example depicted in FIG. 2 , includes a closure element 254 (also referred to as a suction plug) that is secured in the segment 2224 by a retaining assembly 256. Notably, the prior art retaining assembly 256 is coupled to segment 2224 via threads 2228 defined by an interior wall of segment 2224. However, in some embodiments, conduit 222 need not include segment 2224 and conduit 222 may be formed from a single segment (segment 2226) that extends from the pumping chamber 208 to the external surface 210 of casing 206.

Overall, in operation, fluid may enter fluid end 104 (or fluid end 104′) via multiple openings, as represented by opening 216 in FIG. 2 , and exit fluid end 104 (or fluid end 104′) via multiple openings, as represented by opening 214 in FIG. 2 . In at least some embodiments, fluid enters openings 216 via pipes of piping system 106, flows through pumping chamber 208 (due to reciprocation of a plunger 202), and then flows through openings 214 into a channel 108. However, piping system 106 and channel 108 are merely example conduits and, in various embodiments, fluid end 104 may receive and discharge fluid via any number of pipes and/or conduits, along pathways of any desirable size or shape.

Also, during operation of pump 100, the first segment 2124 (of conduit 212), the third segment 2224 (of conduit 222), and the fourth segment 2226 (of conduit 222) may each be “closed” segments. By comparison, the second segment 2126 (of conduit 212) may be an “open” segment that allows fluid to flow from the external surface 210 to the pumping chamber 208. That is, for the purposes of this application, a “closed” segment may prevent, or at least substantially prevent, direct fluid flow between the pumping chamber 208 and the external surface 210 of the casing 206 while an “open” segment may allow fluid flow between the pumping chamber 208 and the external surface 210. To be clear, “direct fluid flow” requires flow along only the segment so that, for example, fluid flowing from pumping chamber 208 to the external surface 210 along segment 2124 and channel 108 does not flow directly to the external surface 210 via segment 2124.

Now turning to FIGS. 3 and 4 , these Figures depict a front view and a side, sectional view, respectively, of an example embodiment of a fluid end 304 formed in accordance with the present application. Additionally, in these Figures, an example embodiment of a closure assembly 400 formed in accordance with the present application is shown installed in the fluid end 304. For simplicity and clarity, these Figures continue to use some reference numerals from the prior art illustrated in FIGS. 1 and 2 ; however, such continuity should not be construed as limiting in any manner and, instead, is only utilized for ease of understanding.

In fact, FIGS. 3 and 4 should not be construed as limiting in any manner. For example, while FIGS. 3 and 4 depict a fluid end 304 with non-circular access segments 3224 that are sealed by non-circular closure assemblies 400, any desirable segments of a fluid end formed in accordance with the present application may be non-circular. That is, segments 2124, 2126, and/or 2226 could be non-circular, either in addition to or instead of non-circular access segments 3224. Additionally or alternatively, only some segments of a particular type of segment could be non-circular (e.g., a subset of the access segments 3224 depicted in FIGS. 3 and 4 ). Still further, while FIGS. 3 and 4 only depict closure assemblies 400 in non-circular access segments 3224, as mentioned, in operation, segment 2124, segment 3224, and segment 2226 are each be completely capped, sealed, plugged, or otherwise closed to prevent fluid from passing through one of these segments to the external surface 310 of casing 306.

Still referring to FIGS. 3 and 4 , but now in combination with FIG. 5 , the closure assembly 400 depicted in these Figures includes at least a sealing assembly 401 formed by a closure element 402 and a seal 461 and/or seal assembly 460 (e.g., a seal 461 and a seal carrier 462). In some embodiments (an example of which is described below), the sealing assembly 401 is self-retaining and, thus, can be installed within a non-circular segment 3224 without any additional components. However, in the embodiment depicted in FIGS. 3-5 , the closure assembly 400 also includes a retaining assembly 470 that retains the assembly 401 within a non-circular segment 3224. More specifically, the retaining assembly 470 is removably coupleable to the closure element 402 and, when coupled thereto, retains the seal 461 adjacent the closure element 402. However, the retaining assembly 470 may also serve to retain the closure element 402 within the non-circular segment 3224. For example, in some embodiments, the retaining assembly 470 may retain the closure element 402 in the non-circular segment 3224 when a suction stroke of a reciprocating component (e.g., plunger 202) urges the closure element 402 into the pumping chamber 308 of the fluid end 304.

As can be seen in FIGS. 4 and 5 , the closure element 402 includes a main body that extends from an interior surface 406 to an exterior surface 410. When the closure element 402 is installed in the non-circular segment 3224, the interior surface 406 is disposed closer to the pumping chamber 308 than the exterior surface 410. That is, the interior surface 406 may be “upstream” (i.e., closer to the pumping chamber 308) of the exterior surface 410. Or, from another perspective, the exterior surface 410 may be “downstream” of the interior surface 406. In fact, in the particular embodiment of at least FIGS. 3-5 , the interior surface 406 of the closure element 402 is disposed in or adjacent to the pumping chamber 308 when the closure element 402 is installed in the non-circular segment 3224. This position may be advantageous not only because it allows the closure assembly 400 to be secured in place without threads, but also because it reduces the overall size of the pumping chamber 308, which is typically advantageous when pumping compressible fluids (i.e., fluids for which the reciprocating pump 100 is intended). To help smooth pressure gradients across the interior surface 406 (e.g., created by fluid moving through the pumping chamber 308), the interior surface 406 may include tapered edges 408.

It is possible to install the closure element 402 in or adjacent the pumping chamber 308 because the overall shape (e.g., the largest dimension) of the closure element 402 is non-circular so that the closure element 402 has an elongated overall dimension 442 and a narrow overall dimension 444, which is smaller than the elongated overall dimension 442. As is described in detail below, dimensions 442 and 444 allow the closure element 402 to be easily inserted into and seated against a non-circular portion of the non-circular segment 3224.

The features of the closure element 402 also facilitate this positioning and installation. More specifically, moving from the exterior surface 410 to the interior surface 406, the closure element 402 includes a closure section 430 and a seating section 438. That is, the closure element 402 includes a closure section 430 adjacent, or at least proximate, to the exterior surface 410 and a seating section 438 adjacent, or at least proximate, to the interior surface 406. The seating section 438 extends radially beyond the closure section 430 and, thus, defines a shoulder 436 between the closure section 430 and the seating section 438. As is described in further detail below, shoulder 436 can engage (e.g. sit on) a seat of the non-circular segment 3224 to secure, or at least orient/align, the closure element 402 within the non-circular segment 3224.

In the depicted embodiment, the closure section 430 has a radial surface 432 that has a non-circular cross-sectional shape. Similarly, the seating section 438 has a radial surface 439 that has a non-circular cross-sectional shape. In fact, the radial surface 439 of the seating section 438 and the radial surface 432 of the closure section 430 have non-circular cross-sectional shapes that are substantially the same. That is, the closure section 430 has a first non-circular cross-sectional shape and the seating section 438 has a second non-circular cross-sectional shape that is smaller than, but similarly proportioned to, the first non-circular cross-sectional shape. Consequently, the closure section 430 and the seating section 438 define a shoulder 436 with a face 437 of substantially constant width and of substantially the same shape as the radial surface 439 and the radial surface 432. In the depicted embodiment, the non-circular shape of these various sections or features is an elongated oval, insofar as “elongated oval” or variations thereof, such as “elongated ovular shape,” are used to denote a shape formed from two semi-circular lines connected by straight lines. However, this is just an example and other non-circular shapes, including one or more ellipses, can be used to achieve a non-circular shape.

In fact, all of the depicted shaping and dimensioning is provided as an example and other embodiments need not have such dimensions and/or shaping. Instead, the closure element 402, and the overall assembly 401, should have dimensions and shaping that correspond with the dimensions and shaping of the non-circular segment 3224. For example, in some embodiments, the seating section 438 might have a non-circular shape and the closure section 430 might have a different non-circular shape or even a circular shape. In fact, in some embodiments, it may be advantageous to have a circular closure section 430. This is because machining non-circular shapes may be more difficult than machining circular shapes. When the closure element 402 includes a circular closure section 430, the non-circular segment 3224 may also include a corresponding circular section. Consequently, a circular closure section 430 may decrease the amount of complex machining required to manufacture the closure element 402 and non-circular segment 3224, which may lower the costs associated with manufacturing the fluid end 304 and the closure assembly 400 presented herein.

However, to preserve the advantages of the non-circular overall shape of the closure assembly 400, when the closure section 430 has a circular shape or a non-circular shape that differs from the non-circular shape of the seating section 438, the overall dimensions of the closure section 430 should not extend beyond the narrow overall dimension 444 of the closure element 402. Any extension beyond the narrow overall dimension 444 might restrict or prevent the closure element 402 from being installed in the non-circular segment 3224. In any case, if only one of the closure section 430 and the seating section 438 includes a non-circular cross-sectional shape, the shoulder 436 may have a different shape than both of these sections. This is because an inner boundary of the shoulder 436 is defined by the closure section 430 and the outer boundary of the shoulder 436 is defined by the seating section 438.

Still referring to FIGS. 4 and 5 , in this embodiment, the closure assembly 400 includes a retaining assembly 470 that is coupled directed to the exterior surface 410 of the closure element 402 and inserted into the non-circular segment 3224 with the closure element 402. That is, the retaining assembly 470, which includes a retaining element 472 and couplers 495, is configured to be disposed entirely within the non-circular segment 3224 of the casing 306 of the fluid end 304 when the closure element 402 is installed within the non-circular segment 3224 to substantially close the non-circular segment 3224. Accordingly, the exterior surface 410 includes a variety of features to securely mount and couple the retaining assembly 470 to the closure element 402.

Specifically, the exterior surface 410 includes a central protrusion 414 that defines a bore 416 and that is surrounded by a plurality of receivers 412 (e.g., bores). Correspondingly, the retaining element 472, which extends from an interior surface 474 to an exterior surface 476, defines bores 478 configured to align with the receivers 412 and a central bore 479 that aligns with the protrusion 414. As can be seen, the bores 478 of the depicted embodiment are countersunk to minimize the distance that couplers 495 installed therein extend beyond the exterior surface 476. Meanwhile, the central bore 479 can sit on the protrusion 414 of the closure element 402 to center the retaining element 472 on the exterior surface 410 of the closure element 402 while the couplers 495 are installed through bores 478 and into receivers 412.

In at least some embodiments, the closure element 402 has a first surface hardness and the retaining assembly 470, or at least portions thereof, such as a retaining element 472 of the retaining assembly 470, have a second surface hardness that is less hard than the first surface hardness. The increased hardness of the closure element 402 will respond to higher loads between the closure element 402 and the fluid end 304 during pumping operations and, thus, will prolong the life of a closure assembly including the closure element 402. However, the entire closure element 402 need not have this increased hardness and, for example, the interior surface 406 and/or tapered edges 408 might have increased hardness as compared to a remainder of the closure element 402. For example, the closure element 402 might have a coating on the tapered edges 408 to provide the increased hardness. In some instances, the coating might provide corrosion resistance, friction resistance, and/or improved sealing, either instead of or in addition to providing increased hardness. Moreover, in some embodiments, the inner wall of the fluid end bore, or at least a portion thereof, may be coated with such a coating, perhaps instead of coating the closure element 402.

Still referring to FIGS. 4 and 5 , but now in combination with FIG. 8A, perhaps the most important aspect of the retaining assembly 470 is that the interior surface 474 of the retaining element 472 bounds a channel 434 defined by the closure section 430 when the retaining assembly 470 is installed on the closure element 402. More specifically, in the depicted embodiment, when the retaining assembly 470 is coupled to the closure element 402, the seating section 438 provides an upstream wall of a channel 434 and the interior surface 474 of the retaining assembly 470 provides a downstream wall for channel 434. Thus, coupling the retaining assembly 470 to the closure element 402 may retain or secure a seal 461, either alone or with a seal carrier 462 (i.e., a spacer), within channel 434, as is shown best in FIG. 8A. In different embodiments, different seals 461 and/or seal carriers 462 may be utilized to extend the lifespan of the closure assembly 400 and/or the fluid end within which it is installed.

Notably, in the depicted embodiment, the seal carrier 462 may be positioned upstream of the seal 461 (such an arrangement is also illustrated in FIGS. 8C and 8H). Additionally, the seal carrier 462 may be a single-piece element (again, such an arrangement is also illustrated in FIGS. 8C and 8H). This arrangement and single piece construction may provide sturdy support for the seal 461, which may improve and/or maintain seal integrity during installation and/or during pumping operations. That is, the seal carrier 462 may backstop the seal 461 and serve as an upstream gland wall for the seal 461 during pumping operations. Testing has found that installing a sealing assembly 401 (i.e., a closure element 402 and a seal assembly 460) without a seal carrier 462 can sometimes cause the seal 461 to warp and/or twist. For example, rolling forces created by translating the seal 461 along a non-circular segment 3224 may twist or warp the seal 461 if the seal 461 is not supported by a seal carrier 462. Thus, the seal carrier 462 may help ensure the sealing assembly 401 is properly installed in a non-circular segment 3224.

FIGS. 8B and 8C illustrate another embodiment of a retaining element 472′ that may be used to form another embodiment of a retaining assembly 470′. The retaining assembly 470′ may operate and/or function in a similar manner to retaining assembly 470. Thus, retaining element 472′ and retaining element 472 are labeled with many like reference numerals and, for brevity, the description of retaining element 472′ included herein focuses on differences between the two embodiments. For example, retaining element 472′ is similar to retaining element 472 because it extends from an interior surface 474 to an exterior surface 476 and includes bores 478 and a central bore 479. Thus, any description of these parts included herein should be understood to apply to retaining element 472′. In contrast, retaining element 472′ includes various features that allow a flexible installation elements 485 to be coupled to the closure assembly 400′.

More specifically, the retaining element 472′ includes holes 481 that extend from the interior surface 474 to the exterior surface 476, or vice versa, so that flexible installation elements 485 can be installed through a main body of the retaining element 472′. Additionally, a connecting passageway 482 is formed on the interior surface 474. The connecting passageway 482 allows a single flexible installation element 485 to be fed through two holes 481 while also extending across a portion of the interior surface 474. This creates a leverage or grip point that a user can use to manipulate the closure assembly 400′, e.g., during installation of the closure assembly 400′ into a fluid end 304. Also, the connecting passageway 482 allows the flexible installation elements 485 to extend along the interior surface 474 without protruding therefrom. Thus, the flexible installation elements 485 will not impact the interface between the interior surface 474 of the retaining assembly 470′ and the exterior surface 410 of the closure element 402 when couplers 495 couple the retaining assembly 470′ to the closure element 402 (e.g., to secure a seal 461 and seal carrier 462 in place therebetween). This placement also ensures that the flexible installation elements 485 do not wear, change the geometry, or otherwise negatively affect the closure element 402 while still enabling easy installation and/or removal of the flexible installation elements 485.

With the holes 481 and connecting passageway 482, the flexible installation elements 485 may be installed onto a retaining element 472′ prior to coupling the retaining element 472′ to a closure element 402, while the interior surface 474 of the retaining element 472′ is still easily accessible. The flexible installation elements 485 can be fed through one hole 481, routed to a second hole 481 via the connecting passageway 482, and fed back out of the retaining element 472′ via the second hole. Then, retaining element 472′ can be coupled to closure element 402 while the flexible installation elements 485 are disposed between the retaining element 472′ and the closure element 402.

In the depicted embodiment, the retaining element 472′ includes two pairs of holes 481 and each pair of holes 481 is connected by a connecting passageway 482. The pairs of holes 481 are located above and below the central bore 479, but within the elongated, ovular arrangement of bores 478. In other embodiments, the holes 481 and/or connecting passageway 482 may be disposed in any desirable location. In fact, in other embodiments, the closure element 402 need not include holes 481 and may include any other features that allow flexible handles 485 to the closure element, such as eye bolts, connected blind holes, etc. However, regardless of how the flexible handles 485 are coupled to the closure element 402, it may be beneficial to arrange flexible handles 485 symmetrically and/or evenly with respect to a center of the retaining element 472′ (e.g., around and/or with respect to bore 479) because symmetrically or evenly spaced flexible installation elements 485 may allow for linear translation that avoids tilting or rotation.

Additionally, in the depicted embodiment, the flexible installation elements 485 are wires, but other embodiments may utilize any elongate, flexible material as flexible installation elements 485. In any case, the flexible installation elements 485 will allow a user/operator to manipulate the retaining assembly 470′ from a location that is exterior of the fluid end 304. This, in turn, reduces the amount of time that operators will need to have their hands inside of a non-circular segment 3224 of the fluid end 304. In some instances, the flexible installation elements 485 may also make it easier for an operator/user to retrieve the retaining assembly 470′ and/or closure assembly 400′ if the retaining assembly 470′ and/or closure assembly 400′ falls into an unwanted location, such as into the pumping chamber 308.

FIGS. 8D, 8E, and 8F illustrate another embodiment of a closure element 420 that may be used to form a closure assembly. The closure element 420 may operate and/or function in a similar manner to closure element 402. Thus, closure element 420 and closure element 402 are labeled with many like reference numerals and, for brevity, the description of closure element 420 included herein focuses on differences between the two embodiments. Perhaps the most notable difference is that a pressure relief conduit 423 extends through closure element 420. Otherwise, closure element 420 extends from an interior surface 406 to an exterior surface 410 that has receivers 412 and a protrusion 414 with a bore 416, like closure element 402, and also has a seating section 438 and closure section 430 like closure element 402.

In the depicted embodiment, the pressure relief conduit 423 is a passageway that extends through the main body of the closure element 420, initiating at entrance 421 and terminating at exit 422. The entrance 421 is disposed on the interior surface 406 and the exit 422 is disposed on the radial surface 432 of the closure section 430, intersecting the channel 434 of the closure section 430 that receives a seal assembly. More specifically, in the depicted embodiment the exit 422 is configured to intersect the channel 434 at a location that is upstream (e.g. closer to a pumping chamber) of a seal 461 positioned in channel 434. Thus, fluid flowing through the pressure relief conduit 423 may enter the channel 434 but the seal 461 will prevent the fluid from bypassing the closure element 420 to exit the segment. Alternatively, the closure element 420 and/or a retaining assembly coupled thereto might include other sealing features that ensure fluid exiting the pressure relief conduit 423 at exit 422 does not escape a fluid end segment in which the closure element 420 is installed. In any case, the pressure relief conduit 423 will not prevent the closure element 420 from closing a segment in which it is installed.

Overall, the pressure relief conduit 423 provides a flow path along which fluid may flow past the seating section 438 without contacting the tapered edges 408 of the interior surface 406 or the shoulder 436 defined by the seating section 438. This prevents, or at least discourages, high pressure fluid from seeping past shoulder 436 and/or creating localized pressure increases at the tapered edges 408 and/or shoulder 436. This diminishment of pressure is important because during pumping operations, the tapered edges 408 and/or the shoulder 436 act as load bearing surfaces and wear of these surfaces past a certain point will cause the closure element 420 to fail. Testing has shown that the pressure relief conduit 423 can reduce or relieve wear generated from localized pressure acting on these surfaces and/or from fluid flowing directly over these surfaces. That is, the pressure relief conduit 423 can allow fluid to flow freely past the seating section 438 and tapered edges 408, which may reduce wear on the seating section 438 and/or tapered edges 408. The diminishment of pressure provided by pressure relief conduit 423 may also help ensure that the closure element 420 remains properly positioned in a fluid end segment. This is because reducing the pressure acting on the bearing surfaces of the closure element 420 (e.g., via interior surface 406 and/or tapered edges 408) will reduce the risk of pressure moving the closure element 420 out of alignment in its segment and/or causing micromovements of the closure element 420.

In the depicted embodiment, the closure element 420 includes a single pressure relief conduit 423 that is generally aligned with a straight section of the elongated ovular shape of the closure element 420. Additionally, the pressure relief conduit 423 is comprised of two straight bores: one bore extending from the entrance 421 in a depth dimension of the closure element 420; and one bore extending from the first bore to the exit 422 along the narrow overall dimension 444 (see FIG. 5 ) of the closure element 420. However, pressure relief conduit 423 is merely an example and other embodiments may include one or more pressure relief conduits 423 of any dimension, shape, or form (e.g., formed from any number of bores) positioned in any desirable location on the closure element 420, provided that the pressure relief conduit 423 provide pressure relief for wear/bearing surfaces of the closure element 420. For example, pressure relief conduit 423 might comprise a diagonal bore extending directly from entrance 421 to exit 422. Additionally or alternatively, a closure element 420 might include two or more pressure relief conduits 423 distributed evenly around the closure element 420 (e.g., aligned with both straight sections of an overall elongated, ovular shape). Still further, in some embodiments, the fluid end might define all or some of a pressure relief conduit, an example of which is discussed below in connection with FIG. 8H.

As one example of how the pressure relief conduit 423 may vary in different embodiments, FIGS. 8G and 8H depict a closure element 420′ that is a slight variation of closure element 420. Closure element 420′ includes pressure relief conduits 425 in the form of grooves on both sides of the closure element 420′, e.g., in alignment with both straight sections of an elongated, ovular shape. While pressure relief conduits 425 do not extend through the closure element 420 to create a flow path that completely avoids the tapered edges 408 and the seating section 438, the pressure relief conduits 425 serve a similar purpose and achieve the same advantages discussed above in connection with pressure relief conduit 423. That is, the pressure relief conduits 425 help reduce pressure on the closure element 420′, which reduces wear and helps preserve or extend the lifespan of the closure element 420′.

To be clear, while the Figures described thus far depict a non-circular closure assembly 400 as a plug-style closure assembly, the same principles, structures, and/or features may also be applicable to a sleeve-style/type closure element and could be used to close and/or seal other non-circular segments of a fluid end, such as a non-circular version of segment 2226. That is, although not shown herein, a sleeve-style, non-circular closure assembly 400 may extend between casing 206 and a packing arrangement. Thus, in some instances, non-circular closure assembly 400 disposed in segment 2226 may be referred to as a packing sleeve. For the purposes of this application, a sleeve- or plug-style closer element may be referred to as a stationary closure element. However, the techniques presented herein need not be limited to stationary closure elements and may also be used in combination with plungers or other movable closure elements, which, for the purposes of this application, may be referred to as movable closure elements. That is, the non-circular concepts presented herein could also be applied to and/or utilized with packing elements.

More specifically, the concepts presented herein (e.g., in connection with closure assembly 400) may be applied to a packing arrangement and a movable closure element. That is, a sleeve-style, non-circular closure assembly may embodied as a packing arrangement and plunger. In such instances, the plunger 202 acts as a closure element and the packing acts as a seal element to form a sealing assembly for the closure assembly presented herein. To be clear, for the purposes of this application, a sealing assembly formed from a packing arrangement and plunger may be referred to as a sealing assembly for a movable closure element. By comparison, sealing assemblies embodied as plug-style or sleeve-style closure elements (with seal elements disposed around a stationary closure element) may be referred to as sealing assemblies for stationary closure elements.

Now turning to FIGS. 6 and 7 , but with continued reference to FIG. 4 as well, the non-circular segment 3224 is generally configured to mate with the various portions of the closure assembly 400. In the depicted embodiment, this is achieved with a non-circular segment 3224 that is entirely non-circular. More specifically, the non-circular segment 3224 includes an access section 320, a sealing section 330, and a seat 332 that are each non-circular. In fact, the access section 320, the sealing section 330, and the seat 332 of the depicted embodiment each have an elongated oval shape, matching the closure assembly.

However, to be clear, for the purposes of this application a fluid end segment may be “non-circular” when one or more portions of the segment is/are non-circular. For example, in some embodiments, the seat 332 may be non-circular and the sealing section 330 and/or the access section 320 may be circular. As a specific example, the access section 320 could have any shape provided that a radius (or major dimension) of the access section 320 is larger than the narrow overall dimension 444 of the closure assembly 400. This will ensure that the closure assembly 400 can be inserted through the sealing section 330 and into the seat 332 (or into the pumping chamber 308, at least temporarily, as is explained in further detail below). Meanwhile, the sealing section 330 can have any shape configured to mate with the channel 434 of the closure assembly 400 so that a seal 461 disposed in the channel 434 can seal against the sealing section 330.

Regardless of which sections of non-circular segment 3224 are non-circular, overall, the non-circular segment 3224 is dimensioned to allow the closure assembly 400 to be inserted through the non-circular segment 3224. More specifically, overall, the non-circular segment 3224 includes a minimal narrow dimension 342 and a minimal elongated dimension 344. Each of these dimensions is configured to allow the closure assembly 400 to be inserted through the non-circular segment 3224 when the closure assembly 400 is disposed in an installation orientation O1 (see FIGS. 18A-18E).

To achieve this, the minimal narrow dimension 342 is larger than a depth of the closure assembly 400, or at least the depth of the closure element 402 (insofar as “depth” is a dimension perpendicular to both narrow overall dimension 444 and elongated overall dimension 442). Meanwhile, the minimal elongated dimension 344 is larger than the narrow overall dimension 444 of the closure assembly 400, or at least a narrow dimension of the closure element 402. Thus, when the narrow overall dimension 444 of the closure assembly 400 is aligned with the minimal elongated dimension 344 of the non-circular segment 3224 and the depth of the closure assembly 400 is aligned with the minimal narrow dimension 342 non-circular segment 3224, the closure assembly 400 (or the closure element 402) may be inserted through the non-circular segment 3224. That is, when the closure assembly 400 (or the closure element 402) is in an installation orientation O1, the closure assembly 400 (or the closure element 402) may be inserted into and through the non-circular segment 3224.

Another important aspect of the non-circular segment 3224 is its seat 332. The seat 332 is configured to support the closure element 402 and, more specifically, to support the seating section 438 of the closure element 402. At the same time, the seat 332 forms a fluid barrier that is essentially in the pumping chamber 308 and, thus, the seat 332 may experience a large amount of wear. Accordingly, the seat 332 includes contoured edges 334 that are designed to smooth the transitions from the pumping chamber 308 and/or from the inlet segment 2126 to the seat 332 and reduce or prevent wear on the casing 306. Notably, the contoured edges 334 eliminate corners, which can be susceptible to wear, between the inlet segment 2126, the pumping chamber 308, and the seat 332. This may be particularly important since the seat 332 may be hard to access for repairs.

Now turning to FIG. 8I, as mentioned above, in some embodiments, the non-circular segment 3224 may also define one or more pressure relief features. In some instances, such features may be defined entirely by the fluid end 304, e.g., with holes or passages formed through the casing 306 of the fluid end 304. In the depicted example, however, the pressure relief features 425′ are grooves formed in alignment with the minimal narrow dimension 342 of the non-circular segment 3224. These passages may have a similar effect, and achieve similar advantages to the pressure relief features 425 of FIGS. 8G and 8H. Additionally or alternatively, pressure relief features 425′ may enhance the effectiveness of pressure relief features, such as pressure relief features 425 of FIGS. 8G and 8H, included on and/or in a closure element. Thus, in at least some instances, the non-circular segment 3224 may—but need not—include pressure relief features 425′ when the closure element includes corresponding pressure relief features.

Now turning to FIGS. 9-17 , these Figures generally depict variations and/or modifications of a non-circular bore and/or a non-circular closure assembly, as compared to the embodiments of FIGS. 3-8C. For brevity, the description of FIGS. 9-17 focuses on differences between the embodiments and does not reiterate descriptions of like components. Instead, FIGS. 9-17 are labeled with like reference numerals where applicable and any description of like parts or components included in this application should be understood to apply to like numbered parts. However, to be clear, the variations and modifications depicted in FIGS. 9-17 should not be interpreted to limit the present application to certain modifications or variations in any manner. Likewise, if a certain difference is not described in detail, this omission should not be interpreted to require that certain parts, components or features must be the same across different embodiments.

That all said, in FIG. 9 , a modified non-circular segment 3224′ is depicted from a side, sectional view. As can be seen, the non-circular segment 3224′ is substantially similar to non-circular segment 3224, except that the non-circular segment 3224 includes an access section 321 that is counter-bored instead of tapered (like access section 320). This counter-bored access section 321 may be advantageous because it may provide easier access to the sealing section 330 and/or seat 332, which may ease servicing and/or manufacturing. As mentioned, manufacturing non-circular bores may be somewhat complicated and, thus, the access afforded by access section 321 may be particularly advantageous for the techniques presented herein.

Next, in FIG. 10 , the closure assembly 400″ is shaped substantially similar to the closure assembly 400, but is now only formed from a closure element 402′. That is, closure assembly 400″ includes a closure element 402′ that is self-retaining and does not include a retaining assembly (like retaining assembly 470). To compensate for this, the closure element 402′ includes an exterior surface 410′ with a radial surface 411 that extends radially beyond the closure section 430. Thus, channel 434′ is defined between the shoulder 436 and the radial surface 411 of the exterior surface 410′.

One other notable difference is that the closure element 402′ includes installation elements 450 extending outwardly, away from the exterior surface 410′. The installation elements 450 provide a grip point on the exterior surface 410′ that can be used during installation and/or removal of the closure element 402 from a non-circular segment 3224 (e.g., like flexible installation elements 485). In the depicted embodiment, the installation elements 450 comprise two U-shaped bars that extend along the narrow overall dimension 444 of the closure element 402′, on either side of a central bore 416′. However, in other embodiments, the installation elements 450 may have any shape and/or may extend in any direction, across any portion of the exterior surface 410′. But, at the same time, it may be beneficial to arrange the installation elements 450 symmetrically and/or evenly with respect to a center of the exterior surface 410 (e.g., around and/or with respect to bore 416′ because symmetrically or evenly spaced installation elements 450 may allow for linear translation that avoids tilting or rotation. The bore 416′ may also be helpful for installation, removal, and/or securing the closure element 402′ within a non-circular segment 3224.

FIGS. 11A and 11B depict yet another embodiment of the non-circular closure assembly presented herein. In this embodiment, the closure assembly 500 includes the closure element 402 and the retaining element 472 of FIGS. 3-8A, but now the retaining assembly 470 also includes a crossbar 502 and an extended coupler 504. As can be seen in FIG. 11A, the crossbar 502 extends across the non-circular segment 3224 (e.g., across the access section 320), so that the crossbar 502 can sit outside the external surface 310 of the casing 306. Then, the crossbar 502 can support an extended coupler 504 that stretches from the external surface 310 to the closure element 402. Thus, the crossbar 502 and extended coupler 504 can further secure the closure element 402 in place in the non-circular segment 3224 (e.g., on a seat 332) and, among other advantages, prevent the closure element 402 from being pushed into or sucked out of the non-circular segment 3224 (or more specifically of the seat 332).

FIGS. 12A and 12B depict a closure assembly 500′ that is a variant of the closure assembly 500 of FIGS. 11A and 11B; but now the closure assembly 500′ incorporates retaining assembly 470′ of FIGS. 8B and 8C. Also, the embodiment of FIGS. 12A and 12B includes certain advantageous features, including: (1) a collar 505 disposed on an upstream end of the extended coupler 504; (2) handle extensions 506 that extend from a downstream end of the extended coupler 504; and (3) a crossbar 502 with a slightly modified geometry. Each of these features may help keep the closure element 402 stable during pumping operations (e.g., during fracking or drilling operations) and/or may help ensure that the closure element 402 is properly installed into the fluid end 304. Testing has revealed that a misalignment between the closure element 402 and its non-circular segment 3224 can lead to micromovements (or larger movements if the misalignment is more pronounced) that cause galling damage of the fluid end 304 that is detrimental to lifespan and/or difficult to repair. Thus, it is important to install a closure element 402 in a non-circular segment 3224 in an aligned position and to maintain the closure element 402 in such a position during pumping operations.

The collar 505 and the extensions 506 may both help prevent or discourage a user from improperly installing the non-circular closure element 402, e.g., in a manner that damages the closure element 402. First, the collar 505 may allow the extended coupler 504 to be coupled to the retaining element 472′ and/or closure element 402 (e.g., via threading), but may limit the depth the extended coupler 504 can extend into the retaining element 472′ and/or closure element 402. This may prevent the extended coupler 504 from damaging the closure element 402 during installation. Meanwhile, the extensions 506 may prevent, or at least discourage, a user from engaging the hex-shaped head of the extended coupler 504 with impact drills or other such torquing tools to drive installation of the extended coupler 504 during installation of closure assembly 500′. This may discourage a user from over-torquing the extended coupler 504 and damaging closure element 402.

The crossbar 502 may include a slot 503 extending inwards from a side of the crossbar 502 and may include stepped inner surfaces 508 at its top and bottom end. The side slot 503 may ease installation while still ensuring that the crossbar 502 securely supports the extended coupler 504. Meanwhile, the stepped inner surfaces 508 may help securely seat the crossbar 502 in the non-circular segment 3224 and against the external surface 310 of the fluid end 304. Or, in other embodiments, stepped inner surfaces 508 may help securely seat the crossbar 502 on a retainer (see, e.g., the retainer 602 of FIG. 16 ) coupled to an external surface 310 of the fluid end 304. In any case, stepped inner surfaces 508 may help the crossbar 502 securely support the closure element 402 during installation and during pumping operations of the fluid end 304 (e.g., during fracking or drilling).

FIGS. 13-15 depict an embodiment that is similar to the embodiments of FIGS. 11A, 11B, 12A, and 12B; however, now closure assembly 600 includes retaining assembly with a crossbar 502′ and extended coupler 504′ that are supported by a retainer 602 in the form of an annular ring on the external surface 310 of the casing 306 (i.e., disposed exteriorly of casing 306). The retainer 602 extends from an interior surface 606 to an exterior surface 608. The interior surface 606 abuts the external surface 310 of casing 306 when the retainer 602 is installed thereon. Additionally, in the depicted embodiment the retainer 602 is an annular ring so that it extends from an internal surface 604 that surrounds and/or defines the exterior opening of the non-circular segment 3224″ to an external surface 610.

More specifically, in the depicted embodiment, both the internal surface 604 and the external surface 610 are non-circular. However, in other embodiments, the retainer 602 need not include a non-circular internal surface 604 and a non-circular external surface 610. For example, the external surface 610 might be circular or the overall retainer 602 might have any desirable shape that can secure the crossbar 502′ to the external surface 310. The key, for at least some embodiments, is that the internal surface 604 extends at least partially over/within the exterior opening of the non-circular segment 3224″ so that the interior surface 606 can define a shoulder at a proximal end of the non-circular segment 3224″. In the embodiment depicted in FIGS. 13-15 , the non-circular segment 3224″ has substantially constant dimensions (e.g., a single non-circular shape) and, thus, the interior surface 606 may be sized based off of a single non-circular shape. However, this non-circular segment 3224″ is merely an example provided for simplicity and, in other embodiments, the retainer 602 can be used with any desirable non-circular segment. For example, in other embodiments, the retainer 602 may be sized to mate with, and extend partially over, a proximal end of an access section of a non-circular bore (e.g., access section 320 or 321).

Additionally, in the embodiment of FIGS. 13-15 , the closure assembly 600 includes a closure element 402″ that does not include a fully bounded seal channel (e.g., like channel 434). Instead, closure element 402″ defines a channel 434′ that is defined by the closure section 430, bounded on an upstream side by the seating section 438, and open on a downstream side. Then, as can be seen best in FIG. 15 , a seal carrier 660 extends between the interior surface 606 of the retainer 602 and the shoulder 436 of the closure element 402″ to support a seal 461 between the closure element 402″ and the non-circular segment 3224″. In different embodiments, the seal carrier 660 may support the seal 461 in any desirable location between the shoulder 436 and the interior surface 606 of the retainer 602.

FIGS. 16A and 16B depict another embodiment that utilizes a retainer 602 as part of the retaining assembly; however, now, the closure assembly 700 includes a closure element 402′″ that is secured adjacent the external surface 310 of the casing 306. One notable advantage of this embodiment is that the closure element 402′ is configured to seal against the retainer 602 and, thus, any wear from this seal occurs on a replaceable part (retainer 602). More specifically, the closure element 402′ resembles the self-retaining closure element 402′ of FIG. 10 , but without the installation elements 450, and thus, defines channel 434′ between its seating section 438 and its exterior surface 410. Meanwhile, the retainer 602 is configured to extend at least partially within the lateral bounds of the non-circular segment 3224″ so that the channel 434′ can sit against the internal surface 604 of the retainer 602, sealing there against.

In still other embodiments, however, the closure element 402″ need not define the channel 434′ and, for example, the channel 434′ could be defined by the retainer 602. That is, the retainer 602 might define a channel for a seal assembly 460 which could transfer wear to the closure element 402″. This might increase the lifespan of the retainer 602, reducing the number of times that the retainer 602 needs to be removed or serviced during pumping operations. Notably, removing the retainer 602 from the fluid end 304 requires multiple bolts/couplers to be removed. By comparison, the closure element 402″ might be able to be removed from the fluid end 304 without removing any bolts/couplers. Thus, it might be easier and/or quicker to service or replace the closure element 402″ than the retainer 602. That is, moving the channel 434′ to the retainer 602 might provide servicing advantages (e.g., less down time). One example of such a channel is depicted in FIG. 17B.

More specifically, the seating section 438 of the closure element 402′″ may sit against the interior surface 606 of the retainer 602, which may secure/retain the closure element 402′″ within the non-circular segment 3224″ when the closure element 402′″ is disposed in an operation orientation O2. At least because the closure element 402″ is secured within the non-circular segment 3224″ adjacent the external surface 310 (and the retainer 602), the coupler 504″ need not be extended. This may also be advantageous because it may reduce the chances that the coupler 504 experiences stresses or torques (e.g., due to misalignment). Also, to be clear, this embodiment is again depicted with a relatively straight/constant, non-circular segment 3224″, but the non-circular segment 3224″ is, again, only provided as a example and the concepts of this embodiment need not be limited to such bores.

FIGS. 17A and 17B depict yet another embodiment of a closure assembly 701 that utilizes a retainer 603 as part of the retaining assembly; however, now, the retainer 603 is provided in the form of a plate (as opposed to a ring, like retainer 602). Aside from its shape, the retainer 603 is similar to retainer 602. For example, retainer 603 extends from an interior surface 606 that abuts the external surface 310 of the casing 306 to an exterior surface 608 and also extends from internal surfaces 604 (which define holes 609) to an external surface 610 that defines a radial boundary of the retainer 603. In the depicted embodiment, the retainer 603 covers multiple non-circular segments 3224″ and provides separate holes 609 for each of these segments. Thus, the retainer 603 includes multiple, disconnected and discrete internal surfaces 604. In other embodiments, however, a single internal surface 604 might span multiple non-circular segments 3224″ or a retainer 603 might only span a single bore segment.

Moreover, in FIGS. 17A and 17B, the closure assembly 701 includes a closure element that is substantially similar to closure element 402′″ and, thus, the closure element is labeled with like numerals. The closure element 402′″ is again (as compared to FIGS. 16A and 16B) secured adjacent the external surface 310 of the casing 306 and thus, realizes similar advantages, but as mentioned above, does not include channel 434′. Instead, the channel 434′ is provided in the casing 306 and/or the retainer 603 to achieve the advantages discussed above. Still further, in FIGS. 17A and 17B, the closure element 402′″ is shown retained in the fluid end 304 by the retainer 603 alone. While this is one option, further components, such as a crossbar and an extended coupler might also be used in combination with retainer 603 if desired.

Now turning to FIGS. 18A-18E, these Figures diagrammatically depict a method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly. Initially, as is shown in FIG. 18A, a first step 802 involves orienting a closure element 402 in an installation orientation O1 and arranging the closure element 402 for insertion into a non-circular segment 3224. As mentioned, in at least some embodiment, the installation orientation O1 aligns a depth of the closure element 402 with a narrow dimension of the non-circular segment 3224 and aligns a narrow dimension of the closure element 402 with an enlarged dimension of the non-circular segment 3224. Thus, once orientated in the installation orientation O1, the closure element 402 can be translated along a lateral axis A1 in a first lateral direction D1. This translational movement moves the closure element 402 through the non-circular segment 3224, from the external surface 310 of the casing 306 to the pumping chamber 308 of the casing 306.

In a second step, the closure element 402 is rotated from its installation orientation O1 to an operational orientation O2 that is angularly offset from the installation orientation O1. For simplicity, this step is depicted in two sub-steps: sub-step 804(1) and sub-step 804(2); however, in other embodiments, this step can be accomplished in one or more operations. For example, the closure element 402 may be rotated about two axes at one time. That said, in FIGS. 18B and 18C, two rotations are shown.

First, in sub-step 804(1), the closure element 402 is rotated about lateral axis A1 in a first rotational direction D2. For example, the closure element 402 may rotate approximately ninety degrees. This may align the narrow dimension of the closure element 402 with the narrow dimension of the non-circular segment 3224 and, thus, in at least some embodiments, it might not be easy to remove the closure element 402 from the pumping chamber 308 via the non-circular segment 3224 after this first rotation. But, since the depth of the closure element 402 may now be aligned with the enlarged dimension of the non-circular segment 3224, it may still be possible to remove the closure element 402 from the pumping chamber 308.

Then, in sub-step 804(2), the closure element 402 is rotated about depth axis A3 in second rotational direction D3. For example, the closure element 402 may rotate approximately ninety degrees. This rotates the enlarged dimension of the closure element 402 into alignment with the enlarged dimension of the non-circular segment 3224 and, thus, orients the closure element 402 for seating in the non-circular segment 3224. That is, after rotating the closure element 402 about two axes, the closure element 402 may be disposed in an operational orientation O2.

Next, in step 806, the closure element 402 is translated is translated along lateral axis A1 in a second lateral direction D4, as is shown in FIG. 18D. The second lateral direction D4 is opposite to the first lateral direction D1 and, thus, this translation moves the closure element 402 towards and/or further into the non-circular segment 3224, causing the closure element 402 to seat in the non-circular segment 3224, eventually moving into installation position P1 (see FIG. 18E). The final seating may also require some lateral adjustments along a longitudinal axis A2, depending on the position of the closure element 402 after the rotation(s).

Notably, in FIGS. 18A-18E, the closure element 402 is installed by itself. In some embodiments (e.g., the embodiment of FIG. 10 ), the closure element 402 may be able to retain a seal on its own and, thus, may define an assembly 401 without any further components. This sealing assembly 401 may also be self-retaining (e.g., like the embodiment of FIG. 10 ) and, thus, installation of the closure assembly 400 may, in some instances, be complete after step 806. However, in other embodiments, the closure assembly 400 may include a retaining assembly 470 that secures and/or retains the closure element 402 and/or a seal 461 within the non-circular segment 3224. For example, step 808 may involve installing a seal 461 and/or a retaining assembly 470 onto a closure element 402 positioned/seated in the installation position P1 to secure the closure element 402 within the 3224. Alternatively, any of the other retaining assemblies depicted herein, or variations thereof, might be installed on a fluid end casing after the sure element 402 positioned/seated in the installation position P1.

Still further, some components of a closure assembly formed in accordance with the present application might be installed prior to completing the method of FIGS. 18A-18E. For example, an annular ring (e.g., retainer 602) might be installed on external surface 310 and left in place before installation and subsequent to removal of a closure element, if desired. In some embodiments, this could reduce downtime during servicing if, for example, the annular ring includes a large number of couplers while the closure element 402 can be installed or removed without removing any couplers (or a single extended coupler 504). To be clear, the installation process may be suitable for, or can be slightly modified for, any embodiment, variation, or modification presented herein. For example, in FIGS. 18A-18E, the part labeled as closure element 402 may be closure assembly that comprises a retaining element 472 and a closure element 402. These two parts may be coupled together prior to step 802, e.g., to capture a seal assembly 460. Then, the closure assembly (or this portion of the closure assembly) may be inserted into the fluid end 304, rotated, and translated, e.g., in accordance with the method of FIGS. 18A-18E.

FIG. 19 provides a specific example of how, in some embodiments, at least some of the method of FIGS. 18A-18E might be completed by way of additional features. First, some steps might be completed by manipulating the closure element 402, with or without retaining element 472 (as well as any seal 461 and/or seal carrier 462 retained therein), with flexible handles 485. As mentioned, hand positioning the closure element 402 in the non-circular segment 3224 by way of flexible installation elements 485 may help properly position the closure element 402 in alignment with a seat of the non-circular segment 3224. Also, before, after, or during step 806 of the method of FIGS. 18A-18E, an extended coupler 504 may coupled to a retaining element 472, as is generally depicted in FIG. 19 . The extended coupler 504 is then retained by a crossbar 502, e.g., at step 810. As mentioned in connection with FIGS. 12A and 12B above, in some instances a collar 505 of the extended coupler 504 and/or handle extensions 506 of the extended coupler 504 may prevent, or at least discourage, a user from over-torquing the extended coupler 504. In turn, this may prevent misalignment of the closure element 402 in the non-circular segment 3224. The extended coupler 504 might also pull or “suck” the closure assembly into a proper seating alignment.

While the invention has been illustrated and described in detail and with reference to specific embodiments thereof, it is nevertheless not intended to be limited to the details shown, since it will be apparent that various modifications and structural changes may be made therein without departing from the scope of the inventions and within the scope and range of equivalents of the claims. In addition, various features from one of the embodiments may be incorporated into another of the embodiments. For example, a retainer, such as a retaining ring, or any other component of a retaining assembly shown with one embodiment of a closure element can be used with any desirable closure element to forma closure assembly of the present application. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure as set forth in the following claims.

It is also to be understood that the sealing assembly described herein, or portions thereof may be fabricated from any commonly used seal materials, such as homogeneous elastomers, filled elastomers, partially fabric reinforced elastomers, and full fabric reinforced elastomers. Suitable resilient elastomeric materials includes, but re not limited to, thermoplastic polyurethane (TPU), thermoplastic copolyester (COPE), ethylene propylene diene monomer (EPDM), highly saturated nitrile rubber (HNBR), reinforced versions of the foregoing materials, such as versions reinforced with fibers or laminations of woven material, as well as combinations of any of the foregoing materials.

Similarly, it is intended that the present invention cover the modifications and variations of this invention that come within the scope of the appended claims and their equivalents. For example, it is to be understood that terms such as “left,” “right,” “top,” “bottom,” “front,” “rear,” “side,” “height,” “length,” “width,” “upper,” “lower,” “interior,” “exterior,” “inner,” “outer” and the like as may be used herein, merely describe points of reference and do not limit the present invention to any particular orientation or configuration. Further, the term “exemplary” is used herein to describe an example or illustration. Any embodiment described herein as exemplary is not to be construed as a preferred or advantageous embodiment, but rather as one example or illustration of a possible embodiment of the invention.

Finally, when used herein, the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc. Meanwhile, when used herein, the term “approximately” and terms of its family (such as “approximate,” etc.) should be understood as indicating values very near to those which accompany the aforementioned term. That is to say, a deviation within reasonable limits from an exact value should be accepted, because a skilled person in the art will understand that such a deviation from the values indicated is inevitable due to measurement inaccuracies, etc. The same applies to the terms “about” and “around” and “substantially.” 

1. A method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly, comprising: inserting a non-circular closure element into a segment of a fluid end casing in a first direction while the non-circular closure element is disposed in a first orientation, rotating the non-circular closure element to a second orientation that is angularly offset from the first orientation with respect to at least one axis of rotation; and moving the non-circular closure element within the segment of the fluid end casing in a second direction that is opposite the first direction to cause the non-circular closure element to seat within the segment.
 2. The method of claim 1, wherein the rotating occurs in a pumping chamber of the fluid end and involves a first rotation of approximately ninety degrees about a first axis of rotation and a second rotation of approximately ninety degrees about a second axis of rotation.
 3. The method of claim 1, further comprising: coupling an exterior surface of the non-circular closure element to a retaining assembly to secure the non-circular closure element within the segment.
 4. The method of claim 3, wherein the retaining assembly includes a retaining element and the method further comprises: installing a seal on the non-circular closure element; and coupling the exterior surface of the non-circular closure element to the retaining element to secure the seal on the non-circular closure element.
 5. The method of claim 3, wherein the retaining assembly includes a retaining element and the method further comprises: coupling the exterior surface of the non-circular closure element to the retaining element prior to insertion of the non-circular closure element into the segment.
 6. The method of claim 5, wherein one or more installation elements are connected to the non-circular closure element and accessible from an exterior of the segment of the fluid end casing so that rotation of the non-circular closure element, movement of the non-circular closure element within the segment, or both, are at least partially effectuated via the one or more installation elements.
 7. The method of claim 6, wherein the one or more installation elements are one or more flexible installation elements that pass between the non-circular closure element and the retaining element.
 8. The method of claim 5, wherein the retaining assembly includes an extended coupler and a crossbar and the method further comprises: coupling an upstream end of the extended coupler to the retaining element; and securing a downstream end of the extended coupler in the crossbar spanning the segment proximate an exterior end of the segment.
 9. The method of claim 8, wherein the extended coupler comprises a collar that limits an amount of torque that can be applied to the non-circular closure element when the extended coupler is coupled to the retaining element.
 10. The method of claim 8, wherein the extended coupler comprises extensions configured to extend beyond the crossbar and limit an amount of torque that can be applied to the non-circular closure element when the extended coupler is coupled to the retaining element.
 11. The method of claim 8, wherein securement of the downstream end of the extended coupler in the crossbar comprises: securing an annular ring to an exterior of the fluid end casing; and seating the crossbar against the annular ring.
 12. The method of claim 5, further comprising: capturing a seal, with or without a seal carrier, between the retaining element and the non-circular closure element.
 13. A method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly, comprising: coupling a retaining element to a non-circular closure element; inserting the non-circular closure element, with the retaining element, into a segment of a fluid end casing; moving the non-circular closure element within the fluid end casing to cause the non-circular closure element to seat within the segment; and securing the non-circular closure element within the segment by way of the retaining element.
 14. The method of claim 13, wherein securement of the non-circular closure element comprises: coupling an upstream end of an extended coupler to the retaining element; and securing a downstream end of the extended coupler in a crossbar spanning the segment proximate an exterior end of the segment.
 15. The method of claim 14, wherein the securement of the non-circular closure element comprises: securing an annular ring to an exterior of the fluid end casing; and seating the crossbar against the annular ring.
 16. The method of claim 13, comprising: inserting the non-circular closure element into the segment of the fluid end casing in a first direction while the non-circular closure element is disposed in a first orientation; and rotating the non-circular closure element to a second orientation that is angularly offset from the first orientation with respect to at least one axis of rotation.
 17. A closure assembly for a fluid end of a reciprocating pump, at least a portion of the closure assembly being installable within a segment of a casing of the fluid end to substantially close the segment, the closure assembly comprising: a closure element that extends from an interior surface to an exterior surface, wherein at least a portion of the closure element has a non-circular cross-sectional shape; and a retaining assembly that is coupleable to the exterior surface of the closure element.
 18. The closure assembly of claim 17, wherein the retaining assembly includes a retaining element, an extended coupler, and a crossbar, wherein an upstream end of the extended coupler is configured to be coupled to the retaining element and a downstream end of the extended coupler is configured to be secured to the crossbar, which is configured to span the segment proximate an exterior end of the segment.
 19. The closure assembly of claim 17, wherein the retaining assembly comprises one or more installation elements extending away from an exterior surface of the retaining element so that that the one or more installation elements are accessible from an exterior of the segment of the casing of the fluid end when the closure element is installed within the segment.
 20. The closure assembly of claim 17, wherein the retaining assembly includes a retainer being disposed exteriorly of the casing of the fluid end and defining a seat on which the closure element, a portion of the retaining assembly, or both the closure element and the portion of the retaining assembly may sit. 